Pipe clamps of the type utilizing split flexible bands for encircling the pipe have heretofore been provided with looped opposed ends carrying trunnion loading bars, the looped ends being drawn toward each other by bolts extending through the trunnion bars. In instances where the trunnion loading bars are made from solid or tubular stock, one of the trunnion bars is provided with a threaded aperture therethrough while the other of the trunnion bars is provided with an unthreaded aperture. The bolt is inserted through the unthreaded aperture and then threaded into the threaded aperture of the other trunnion bar, and such an arrangement requires that the clamp be provided with special means to retain the bolt in one of the trunnion loading bars prior to assembly of the clamp on a pipe. Additionally, the installation of such a clamp on a pipe in an excavation is oftentimes done under adverse conditions with the pipe usually covered with muddy water. The person installing the clamp often has difficulty in threading the bolt through the threaded aperture in one of the trunnion bars.
Other clamps of the type utilizing solid or tubular trunnion bars with apertures therethrough rely on a nut and bolt arrangement rather than having the apertures in one of the trunnion bars threaded. This type of clamp is even more difficult to install under adverse conditions as the nuts must be removed from the bolts prior to installation and thus require the person installing the clamp to thread the nuts onto the bolts at the site.
The use of trunnion bars in the looped ends has provided clamps wherein high load can be applied by the band on the pipe; however, the difficulty in installing the clamp on a pipe at the site has outweighed the utility resulting from the use of trunnion bars.
In order to provide pipe repair or service clamps with an arrangement whereby the clamp can be applied to a pipe under adverse conditions, flexible band clamps have been provided with rigid lugs on their opposed split ends, one of the lugs having an aperture therethrough and the other lug having an open slot therein. The lug having the aperture carries the bolt and the nut prior to installation on a pipe, and since the aperture is quite large, the bolt and nut can be swung relative thereto so that the end of the bolt having the head thereon can be swung into the slot on the other lug prior to nut tightening. In some situations the lug carrying the bolt and the nut prior to assembly is provided with means for pivotally carrying the bolt and the nut to enable greater pivotal movement of the bolt. The type of clamp with the "flip-in" bolt and nut arrangement which has required cast lugs has several disadvantages, even though it may be easily installed onto a pipe under adverse conditions. First, means must be provided for attaching the lugs to the ends of the thin flexible band, this making the clamp more costly to manufacture and heavier. Another disadvantage of the clamps utilizing the cast lugs is that the lugs project outwardly from the clamp and make wrapping of the clamp more difficult. While the problem of wrapping for corrosion protection was increased, the profile of the clamp was also increased, thus increasing the likelihood of the clamp being hit by digging equipment during future excavations.